This invention relates to the field of tape media read-write head positioning devices.
Read-write head positioning devices used in magnetic tape drives to align the read-write head with data in the magnetic tape often incorporate a two actuator design. One actuator provides coarse positioning to move the read-write head between data bands. The other actuator provides fine positioning to maintain alignment between the read-write head and the data tracks. The two actuators are usually mounted in a xe2x80x9cpiggybackxe2x80x9d arrangement with the fine position actuator riding on the coarse position actuator.
The coarse positioning actuator is typically a linear stage driven by a stepper motor. Stepper motors have the ability to move the linear stage anywhere across the width of the magnetic tape at modest speeds. However, most stepper motors lack the accuracy and bandwidth necessary to maintain alignment between the read-write head and the data tracks as the magnetic tape moves across the face of the read-write head.
The fine positioning actuator is typically a voice coil mounted on the linear stage and held at a rest position by some type of spring. A voice coil actuator provides micron to submicron precision positioning at a bandwidth of hundreds to thousands of hertz. However, a single voice coil and spring combination that can meet the fine positioning requirements across the full width of the tape is expensive and unnecessary.
The combination of coarse positioning and fine positioning is desired to meet the requirements associated with reading and writing on the magnetic tapes. Current solutions involve two actuators, their respective controllers, and a significant amount of hardware. What is desired is a simpler positioning device that requires only one actuator and minimal hardware.
Under the invention, an apparatus for positioning a transducer includes a fixed frame and a moving frame movably associated with the fixed frame such that the moving frame is movable between a plurality of discrete positions relative to the fixed frame. A carriage is movably associated with the moving frame and has the transducer mounted thereon. The apparatus further includes an actuator associated with the carriage. The actuator is operative to move the moving frame to a selected discrete position of the plurality of discrete positions, and is further operative to move the carriage relative to the moving frame when the moving frame is in the selected discrete position.
Further under the invention, an apparatus for positioning a transducer includes a fixed frame and a moving frame movably associated with the fixed frame. A carriage having the transducer mounted thereon is movably associated with the moving frame such that the carriage is movable between a plurality of discrete positions relative to the moving frame. The apparatus further includes an actuator associated with the moving frame. The actuator is operative to move the carriage to a selected discrete position of the plurality of discrete positions, and is further operative to move the moving frame relative to the fixed frame when the carriage is in the selected discrete position.
Advantageously, in each of the above embodiments, a single actuator may be used to provide coarse and fine positioning of the transducer. The actuator in each of the above embodiments may be a voice coil, for example. Furthermore, coarse and fine positioning may be achieved by varying the current through windings of the actuator.
A method is also provided for positioning a transducer disposed on a carriage, wherein the carriage is resiliently coupled to a moving frame, the moving frame is movably associated with a fixed frame such that the moving frame is movable between a plurality of discrete positions, and an actuator is associated with the carriage for displacing the carriage. The method includes activating the actuator to displace the carriage so as to move the moving frame from a current discrete position of the plurality of discrete positions to a desired discrete position of the plurality of discrete positions.
Further under the invention, a method is provided for positioning a transducer disposed on a carriage, wherein the carriage is movably associated with a moving frame such that the carriage is movable between a plurality of discrete positions relative to the moving frame, the moving frame is resiliently coupled to a fixed frame, and wherein an actuator is associated with the moving frame for displacing the moving frame. The method includes activating the actuator to displace the moving frame so as to move the carriage from a current discrete position of the plurality of discrete positions to a desired discrete position of the plurality of discrete positions.
These and other objects, features and advantages will be readily apparent upon consideration of the following detailed description in conjunction with the accompanying drawings.